40 CFR 61.192 - Standard.

No source at a Department of Energy facility shall emit more than 20 picocuries per square meter per second (pCi/(m
2-sec)) (1.9 pCi/(ft
2-sec)) of radon-222 as an average for the entire source, into the air. This requirement will be part of any Federal Facilities Agreement reached between Environmental Protection Agency and Department of Energy.